1. Field of the Invention
Embodiments of the invention relate to the field of memory devices, and more specifically, to redundancy in memory devices.
2. Description of Related Art
Block redundancies are normally used to repair defects that cannot be fixed with row or column redundancies in non-volatile memories such as flash memories. Defect modes such as word-line to bit-line shorts, word-line to substrate shorts (e.g., stuck-at-one or stuck-at-zero), etc. fall into the category for block repair.
Column defects such as bit-line to bit-line shorts occur often in the production of non-volatile memories. Although block redundancies may be used to repair such defects, they are costly due to increase in die size. Typically, each redundant block may result in 0.5% to 1% increase in die size depending on the block size and the density of the memory device.